Re: [lwip-users] RE: lwip-users Digest, Vol 7, Issue 6

[Leon Woestenberg]

Hello Eric,

Eric Shufro wrote:
> What is the formal way to initialize lwip? What functions do you call and in
> what order (including dhcp) and especially setting up the lwip output
> pointer and registering it with the driver. That just eludes me.
See the contrib/ports/unix/proj/minimal/ directory for a minimal 
application that brings up the lwIP stack together with an echo service.

> As for the cs8900 driver, what is the most recent version, and where can it
> be found? (is it in the c16x port? -> doesn't seem like it's the most
> recent).
>
Most recent versions are always in CVS. It is worthwhile using a cvs 
client to synchronize against it.

Savannah does not provide daily CVS snapshot archive that I am aware of,
but I may be wrong here. (It used to... I cannot find them on Google 
though).

> Leon, any experience with the cs8900 in IO mode? I am probably going to have
> to re-write the driver for it. If I do, I will resubmit it as an alternative
> to the memory mode driver you have provided. Thank you for providing a good
> start.
My driver uses cs8900 I/O mode, not memory mode.

But note that my processor architecture (c16x) does map the sixteen 
cs8900a I/O registers in memory, that's why you may be confused.

cs8900a memory mode means that one has random access to received packets 
etc, inside the cs8900a buffer. In our case, we move the packet 
word-by-word into system RAM memory, then have lwIP examine it there.

This is the usual way, and memory access does not improve performance by
more than 5%.

Using the PBUF_REF type on received packets, together with cs8900a 
memory code, would be very elegant though.

Regards,

Leon.